Catalysis

Composite number

Engineering

Chemical physics

Electrochemistry

Materials science

Density functional theory

Dopant

Redistribution (election)

Carbon monoxide

Carbon fibers

Chemical engineering

Faraday efficiency

Porosity

Physical chemistry

Nanotechnology

Organic chemistry

Mathematics

Politics

Political science

Doping

Thermal treatment

Computational chemistry

Composite material

Combinatorics

Chemistry

Electrode

Topology (electrical circuits)

Electrochemical reduction of carbon dioxide

Optoelectronics

Advanced Materials

Topological defects, with an asymmetric local electronic redistribution, are expected to locally tune the intrinsic catalytic activity of carbon materials. However, it is still challenging to deliberately create high-density homogeneous topological defects in carbon networks due to the high formation energy. Toward this end, an efficient NH3 thermal-treatment strategy is presented for thoroughly removing pyrrolic-N and pyridinic-N dopants from N-enriched porous carbon particles, to create high-density topological defects. The resultant topological defects are systematically investigated by near-edge X-ray absorption fine structure measurements and local density of states analysis, and the defect formation mechanism is revealed by reactive molecular dynamics simulations. Notably, the as-prepared porous carbon materials possess an enhanced electrocatalytic CO2 reduction performance, yielding a current density of 2.84 mA cm-2 with Faradaic efficiency of 95.2% for CO generation. Such a result is among the best performances reported for metal-free CO2 reduction electrocatalysts. Density functional theory calculations suggest that the edge pentagonal sites are the dominating active centers with the lowest free energy (ΔG) for CO2 reduction. This work not only presents deep insights for the defect engineering of carbon-based materials but also improves the understanding of electrocatalytic CO2 reduction on carbon defects.

Ammonia Thermal Treatment toward Topological Defects in Porous Carbon for Enhanced Carbon Dioxide Electroreduction